The invention is directed to a method and an encapsulation for encapsulating electrical or electronic components or assemblies with a housing formed by at least two joined housing parts and having terminal legs guided to the outside.
It is known that electronic components such as integrated circuits or assemblies including hybrid circuits, and which are enveloped with thermoset plastics, can be destroyed by internal stresses or corrosion. The internal stresses are produced by plastics shrinkage as well as by different thermal expansions of the component or the assembly, system carrier, and/or the plastics. An envelope is therefore required which compensates both the stresses and the different expansions, and also offers protection against internal corrosion. Dependent on the structure, integrated circuits, for example, are presently covered in a cost intensive way with a protective layer before application of the envelope of thermoset plastic. This protective layer is formed, for example, of a plasma nitride, polyimide, and/or gel drops. The regions outside of the chip such as for example the chip circumference and the contact location between the bond wire and the allocated terminal leg, thus remain unprotected. When enveloping assemblies, an elastic intermediate layer for protecting the components and the circuit is employed and is formed, for example, of silicone gel or of an elastic acrylate.
Methods and encapsulations for encapsulating electrical or electronic components or assemblies are also already known wherein the components or assemblies are accommodated in a closed housing from which only the terminal legs are conducted out. These housings formed of at least two joined housing parts offer a mechanical protection of the components or assemblies and, in particular, of the sensitive connections to the terminal legs as well. On the other hand, however, moisture can penetrate into the housing due to the joining together of the housing parts and can penetrate in the passage region of the terminal legs, i.e. the protection against internal corrosion is inadequate.